Traveling device moving along elongated member

ABSTRACT

A traveling device traveling along an elongated tube or member has an elastic contractable body expanding in radial directions to cause a contractive force in axial directions when supplied with pressurized fluid into the body. Mounting members are connected to respective ends of the elastic contractable body, and elastic member are arranged between the mounting members causing force resisting to the contractive force of the elastic contractable body. An anchoring structure is fixed to the mounting members and expands when supplied with pressurized fluid into the anchoring structure. In case of a large diameter column or tube, the traveling device comprises a plurality of elastic contractable bodies and a pair of frames having a shape and a size encircling the column or enclosed in the tube other than the components above described. With this arrangement, the traveling device is caused to travel along the elongated member or in the tube by supplying the pressurized fluid into and exhausting from the elastic contractable body in connection with alternate supplying the pressurized fluid into the exhausting from the anchoring member.

BACKGROUND OF THE INVENTION

This invention relates to a traveling device advancing and retreatingalong a tubular or columnar member by alternately supplying andexhausting a pressurized fluid into and from an elastic contractablebody. The body is adapted to cause a contractive force in its axialdirection due to radial expansion when supplied with the pressurizedfluid.

In chemical plants, nuclear power stations and the like, there are agreat number of pipe lines connected for chemical reaction, energyconversion processes and the like. In order to make operate these plantssafely and effectively, it is necessary to maintain and inspect thesepipe lines periodically. Inspection in the pipe lines is also needed, asthe case may be.

However, it is sometimes impossible for an operator to directly inspectthe inside of the pipe lines due to their small inner diameters andexternal conditions.

In such a case, damage of the pipe lines and existence or amount ofsubstances accumulated in the pipe lines have been inspected by atraveling device having wheels or pawls and driven by an electric orhydraulic motor, which was provided with a small type television cameraor fiber scope.

With such a hitherto used traveling device, as the electric or hydraulicmotor is used as driving means which is probably required to have speedreduction means, the traveling device is heavy and bulky so thatapplicable tubes are limited. In practice, applicable tubes are limitedto those of 10^(B) -40^(B) (JIS G3452, nominal diameters: 10"-40"). Inthe case of a traveling device having levers for embracing a tube line,it is exclusively applicable to only tube lines whose cross-sections aresymmetrical such as circular cross-sections. In addition, such atraveling device cannot travel along an outside of a tube line due togrooves and protrusions formed on an outer surface of the tube line.Moreover, the traveling device is so heavy that it is only applicable tohorizontal pipe lines or slightly inclined or curved portions of pipelines. What is worse still, the electric or hydraulic motor as drivingmeans tends to cause sparks and heating in operation so that the use ofsuch a motor is disadvantageous in chemical plants including petroleumrefineries treating inflammable or explosive materials.

In the case of inspecting outsides of long pipe lines or coating outersurfaces of chimneys in plants, scaffoldings are provided adjacentthereto, on which inspectors or workers stand.

However, assembling and disassembling of the scaffoldings aretime-consuming and expensive operations. In addition, working on suchscaffolding is often very dangerous because the scaffoldings are likelyto undergo wind, vibrations and the like.

SUMMARY OF THE INVENTION

It is a primary object of the invention to provide a traveling devicealong an elongated member such as a pipe line or a column, whicheliminates all the disadvantages of the prior art and is small andlight, superior in explosion-proofness and which is applicable to tubesin a wide range such as those having various cross-sections or havinggrooves and protrusions on outer surfaces.

In order to achieve this object, the traveling device traveling along anelongated member according to the invention comprises an elasticcontractable body expanding in radial directions to cause a contractiveforce in axial directions when supplied with pressurized fluid into thebody, mounting members connected to respective ends of said elasticcontractable body, an elastic member arranged between said mountingmembers causing force resisting to said contractive force of saidelastic contractable body, and anchoring means fixed to said mountingmembers and expanding when supplied with pressurized fluid into saidanchoring means, thereby causing the traveling device to travel alongsaid elongated member by supplying the pressurized fluid into andexhausting from the elastic contractable body in connection withalternate supplying the pressurized fluid into and exhausting from theanchoring means.

In a second aspect of the invention, a traveling device traveling alongan elongated member comprises a pair of frames having a shape and a sizeencircling said elongated member, at least one elastic contractable bodyhaving both ends connected to said pair of frames, respectively, andexpanding in radial directions to cause contractive force in axialdirections when supplied with pressurized fluid into the body, anelastic member deformable in response to contractive movement of theelastic contractable body, and anchoring means expandable at leastinwardly of said frames to engage an outer surface of said elongatedmember when supplied with pressurized fluid into the anchoring means,thereby causing the traveling device to travel along said elongatedmember by supplying the pressurized fluid into and exhausting from theelastic contractable body in connection with alternate supplying thepressurized fluid into and exhausting from the anchoring means.

In a third aspect of the invention, a traveling device traveling alongan elongated tube comprises a pair of frames having a shape and a sizeenclosed in said elongated tube, at least one elastic contractable bodyhaving both ends connected to said pair of frames, respectively, andexpanding in radial directions to cause contractive force in axialdirections when supplied with pressurized fluid into the body, anelastic member deformable in response to contractive movement of theelastic contractable body, and anchoring means expandable at leastoutwardly of said frames to engage an inner surface of said elongatedtube when supplied with pressurized fluid into the anchoring means,thereby causing the traveling device to travel in said elongated tube bysupplying the pressurized fluid into and exhausting from the elasticcontractable body in connection with alternate supplying the pressurizedfluid into and exhausting from the anchoring means.

With this arrangement, the pressurized fluid is supplied into theforward positioned anchoring means so as to expand to urge it against aninner surface of an elongated tube or an outer surface of a elongatedmember, whereby the anchoring means is fixed to the elongated tube ormember. At this moment, the pressurized fluid is not supplied to therearward positioned anchoring means.

The pressurized fluid is then supplied into the elastic contractablebody which is expanded in radial directions to contract in axialdirection against a force of the elastic member or a compression coilspring. However, as the forward positioned anchoring means is fixed tothe elongated member, the rearward positioned frame is attracted in theforward direction by the con raction of the elastic contractable bodywhose one end is fixed to the frame.

After completion of the forward movement of the rearward positionedframe, the pressurized fluid is supplied into the rearward positionedanchoring means which is thus expanded and fixed to the elongatedmember. The pressurized fluid is exhausted from the forward positionedanchoring means and from the elastic contractable body, so that theforward positioned frame is advanced by release of the energyaccumulated in the elastic member or the compression coil spring due tothe contraction of the elastic contractable body.

Thereafter, the pressurized fluid is again supplied into the forwardanchoring member which is thus expanded and fixed to the elongatedmember. In this manner, the pressurized fluid is supplied into andexhausted from the respective anchoring means and the elasticcontractable body, respectively, in the sequence above described,thereby the traveling device is moved along the elongated member.

As can be seen from the above explanation, if it is desired toretraction the traveling device, the retract of the device can beaccomplished only by changing the sequence for supplying and exhaustingthe pressurized fluid.

In order that the invention may be more clearly understood, preferredembodiments will be described, by way of example, with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a front elevation, in partial section, of a traveling devicetraveling in an elongated tube;

FIG. 1b is a perspective view illustrating rolling means applicable tothe traveling device shown in FIG. 1a;

FIG. 2a is a partial sectional view illustrating an elastic contractablebody suitable for the traveling device according to the invention;

FIGS. 2b and 2c illustrate modifications of the elastic contractablebody;

FIGS. 3a and 3b are sectional views illustrating mounting members usedin the traveling device shown in FIG. 1a;

FIGS. 4a, 4b and 4c are perspective views for explaining steps of fixingthe anchoring means to the mounting member;

FIGS. 5a-5f are views for explaining traveling operations of the devicein a tube according to the invention;

FIG. 6a is a front view illustrating another embodiment of theinvention;

FIG. 6b is a sectional view illustrating the traveling device shown inFIG. 6a;

FIGS. 7a and 7b are sectional views illustrating parts of thecontractable body shown in FIG. 6a on enlarged scale;

FIGS. 8a-8e are views for explaining traveling operations of the deviceaccording to the invention;

FIG. 9 is a view for explaining the traveling of the device according tothe invention along a curved tube;

FIGS. 10a and 10b are front views illustrating other embodiments of theinvention;

FIG. 11a is a front elevation illustrating a further embodiment of theinvention;

FIG. 11b is a partial sectional view illustrating the traveling deviceshowing FIG. 11a;

FIGS. 12a-12e are views for explaining traveling operations of thedevice according to the invention;

FIG. 13 is a view for explaining the traveling of the device accordingto the invention in a curved tube; and

FIG. 14 is a front elevation illustrating a further embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a front view illustrating in partial section a travelingdevice traveling in a pipe according to the invention. The devicecomprises an elastic contractable body 2, mounting members 4a and 4bintegrally connected to ends of the contractable body 2, a compressioncoil spring 6 as an elastic member and anchoring means 8 fixed to themounting members 4a and 4b.

As shown in FIG. 2a, the elastic contractable body 2 comprises a tubularbody 10 made of rubber or a rubber-like elastomer covered by areinforcing braided structure 12 made of preferably high tensilestrength fibers and closed at ends by closure members 14. At least oneof the closure members 14 is formed with a connecting aperture 18communicating with an inner cavity 16 in the tubular body 10. Referencenumeral 20 denotes male screws or external thread portions which serveto secure the mounting members to the elastic contractable body 2. Clampsleeves 22 serve to prevent the tubular body and the braided structurefrom being dislodged from the closure members.

Connected to the connecting aperture 18 is a pipe line including apressure source (not shown) for operation, for example, an aircompressor and a three-way valve. When compressed air is suppliedthrough the pipe line into the inner cavity 16, the elastic contractablebody 2 is expanded in diameter to cause a contractive force in its axialdirections. On the other hand, when the compressed air is exhausted fromthe inner cavity, the elastic contractable body 2 regains its initiallength with the aid of its elasticity.

FIGS. 2b and 2c illustrate a slight modification of one end of theclosure member 14 wherein the end is formed with a female screw orinternal thread portion 14a for facilitating the connection of the pipeline from the pressure source and with an annular groove 14b forreceiving a snap ring for fixing one end of the elastic contractablebody 2. In FIG. 2c, reference numeral 14c denotes a female screw orinternal thread portion formed in one end 20a of the elasticcontractable body 2.

To the ends of the elastic contractable body 2 shown in FIG. 2a areconnected through the closure members 14 the mounting members 4a whosesection are shown in FIGS. 3a and 3b. The mounting member 4a shown inFIG. 3a includes a female screw or internal thread portion 24 adapted toengage the male screw portion 20 of one of the closure members, and anaperture 26 for receiving one part of the clamp sleeve 22. The mountingmember 4b shown in FIG. 3b includes also an aperture 26 for receivingone part of the other clamp sleeve 22. The aperture 26 has a connectingaperture connecting therewith. Into the connecting aperture is insertedthe closure member 14 other than the closure member 14 having the malescrew portion 20. Onto the male screw portion 20, extending from themounting member 4b, a coupling shown in phantom lines in FIG. 2a isscrew-threaded to integrally connected it to the elastic contractablebody.

Moreover, mounting members 4a and 4b include on their sides jointsurfaces 28a for fixing thereon the anchoring structure 8 which isexpandable when supplying a pressurized fluid. In this embodiment, asschematically shown in FIG. 4a, a tubular body 30 made of rubber or arubber-like elastomer is mounted on the joint surface 28a of themounting member 4a or 4b, and the clamp sleeve 32a is fitted on thetubular body 30 and calked thereon to fix the tubular body 30 to themounting member 4a or 4b. Thereafter, the free portion of the tubularbody 30 is reversed and fitted on the joint surface 28b of the mountingmember. The clamp sleeve 32b is fitted on the reversed free portion ofthe tubular body 30 and caulked thereon to fix the tubular body 30 tothe mounting member, thereby forming the anchoring structure 8.

The mounting members 4a and 4b are provided with supply and exhaustpassages 30a and 30b, respectively, for supplying the pressurized fluidinto and exhausting from the anchoring structure 8. In this embodiment,each mounting member is provided with the two supply and exhaustopenings so that a great amount of the pressurized fluid can be suppliedinto and exhausted from the anchoring structure in a relatively shortperiod of time. However, the number of the openings may be increased ordecreased, if required. Although the anchoring structure is the tubularbody made of rubber or a rubber-like elastomer, a tubular bodyreinforced by reinforcing layers may be used in consideration that thetubular body is repeatedly expanded and abuts against an inner wall of apipe to which the device is applied.

According to the invention, the elastic member 6 is arranged between themounting members 4a and 4b which are connected to the respective ends ofthe elastic contractable body 2 and have the anchoring structure 8,respectively. The elastic member is the compression spring 6 in thisembodiment, which is required only to have a function elasticallydeformed by both the mounting members 4a and 4b moving toward each otherowing to the axially contracting movement of the elastic contractablebody 2 when supplying the pressurized fluid and on the other hand urgingthe mounting members 4a and 4b away from each other owing to the releaseof the elastic energy in response to the decrease of the contractiveforce of the elastic contractable body 2 due to the exhaust of thepressurized fluid from the elastic contractable body 2. In order tofacilitate arranging the compression spring 6 between the mountingmembers in this embodiment, rims 34 are provided on the ends of themounting members opposed to each other as shown in FIGS. 3a and 3b.

In order to make smooth the movement of the device in a tube in thisembodiment, rolling means 36 as shown in FIG. 1b are used utilizing theclamp sleeves 32b. An outer diameter of the device including the rollingmeans 36 is preferably smaller than outer diameters of the anchoringmeans 8 expanded by the pressurized fluid supplied thereinto or an innerdiameter of the tube in which the device travels, but is larger than aouter diameter of the device including the anchoring contracted by theexhaust of the pressurized fluid. The numbers and positions of therolling means may be determined according to used conditions of thedevice.

The respective steps of operation of the traveling device according tothe invention are shown in FIGS. 5a-5f. FIG. 5a illustrates thetraveling device arranged in a tube in which the device travels.

The supply and exhaust passages 30a formed in the mounting member 4a areconnected to each other through a connecting pipe 40. On the other hand,to the supply and exhaust passages 30b, formed in the mounting member4b, is connected a supply and exhaust pipe 42 which is connected to thepressure source (not shown) and includes valve means, for example, athree-way valve for controlling the supply and exhaust of thepressurized fluid. One end of a further connecting pipe 44 spaced fromand extending in parallel with the elastic contractable body isconnected to one of the supply and exhaust openings 30a of the mountingmember 4a, and the other end of the further connecting pipe 44 isconnected to a through-aperture (not shown) formed in the mountingmember 4b. To the other end of the through-aperture is connected asupply and exhaust pipe 46 including a three-way valve.

An arrow A in FIG. 5b illustrates a direction in which the device is tobe traveled. First, the pressurized fluid is supplied into the anchoringstructure 8 forward positioned through the supply and exhaust pipe 46 soas to expand the anchoring structure 8 so that the forward positionedanchoring structure 8 is pressed to an inner wall of the tube so as tobe held thereat.

The pressurized fluid is then supplied into the elastic contractablebody 2 through a supply and exhaust pipe 48 which is connected to asuitable pressure source and includes valve means such as a three-wayvalve for controlling the supply and exhaust of the pressurized fluid soas to expand the elastic contractable body in diameter and contract inaxial directions. The contractive force caused in the elasticcontractable body 2 depends upon pressure of the pressurized fluid.Therefore, the compression spring 6 can be compressed by suitablyselecting the pressure of the pressurized fluid. Accordingly, themounting member rearward positioned on the side of the supply andexhaust pipe 48 moves forward compressing the compression spring 6 asshown in FIG. 5c.

The pressurized fluid is then supplied through the supply and exhaustpipe 42 into the anchoring structure 8 rearward positioned on the sideof the supply and exhaust pipe 42 to expand the anchoring structure 8 sothat the anchoring structure 8 is pressed to the inner wall of the tubeand fixed thereat as shown in FIG. 5d.

The pressurized fluid is then exhausted through the pipe 46 from theforward positioned anchoring structure 8 so that the anchoring structurecontracts with the aid of its elastic restoring force as shown in FIG.5e.

The pressurized fluid is then exhausted through the pipe 48 from theelastic contractable body 2 to eliminate the contractive force so thatthe forward positioned mounting member is forward moved by the action ofthe elastic force stored in the compression spring.

By suitably supplying the pressurized fluid into and exhausting it fromthe respective anchoring structure and the elastic contractable body inthe manner above described, the device according to the invention can bemoved in the forward direction in the tube shown by the arrow A.

As can be seen from the above description, for the purpose of retractingthe traveling device, the order for supplying the pressurized fluid intoand exhausting from the respective anchoring structure may be changed.

Various changes and modifications may be made in the invention withoutdeparting from the spirit and scope thereof. Although the single elasticcontractable body is used in this embodiment, a plurality of the elasticcontractable bodies may be used. Moreover, in order to apply theinvention to a tube having a great diameter, a plurality of travelingdevices as above described may be used, whose respective mountingmembers are fixed to a pair of annular members corresponding in size toa diameter of tube in which the traveling device travels.

As can be seen from the above explanation, the traveling deviceaccording to the invention utilizes an elastic contractable body whichis of light weight and very small in cross-sectional dimension incomparison with other actuators and capable of causing contractiveforces in axial directions by expanding in diameter when pressurizedfluid is supplied into the elastic contractable body. Therefore, thereduction of size and weight of the traveling device can beaccomplished. Accordingly, the traveling device according to theinvention can be applied to tubes having small diameters of the order of2^(B) (JIS G3452, nominal diameter: 2"). Moreover, the traveling deviceaccording to the invention is applicable to vertically arranged tubes towhich traveling devices of the prior art are scarcely applicable.

Contrasted with traveling devices using wheels or pawls of the priorart, the traveling device according to the invention is fixedly held ina tube by means of anchoring members expanded by supplied pressurizedfluid. Therefore, contacting areas to an inner wall of the tube arelarge and hence the compressive stresses acting upon the inner wall aresmall, so that the device can be securely held without slipping and theinner wall is not damaged.

According to the invention, moreover, the traveling device utilizes theelastic contractable body as an actuator. Accordingly, there is no riskof the occurrence of sparks and heating so that the traveling deviceaccording to the invention can be applicable in an explosive atmosphere.Moreover, the traveling device according to the invention can travel ata very low speed without any trouble by adjusting the supplying andexhausting of the pressurized fluid. Furthermore, if the pressurizedfluid is compressed air, a plant using the devices according to theinvention is not detrimentally affected even if the devices are damagedin comparison with devices using hydraulic systems of the prior art.

FIGS. 6a and 6b are a front elevation of another embodiment of thetraveling device traveling along an outside of a tube and a partiallycut away side view thereof. A pair of frames 51 are arranged spacedapart from each other and annular having an inner diameter larger than atube B along which the device travels. Each frame 51 is made splitableso that the frame is applicable to a tube at a mid portion thereof. Inpractice, each frame 51 is divided into two segments whose one ends arepivotally connected by a hinge 52 and the other ends are connected byknown means, for example, a connecting plate 53 and set screws. In thepair of frames, four elastic contractable bodies 54 are arranged inparallel with axial directions of the frames and equally spaced fromeach other in circumferential directions of the frames.

The elastic contractable bodies 54 shown in FIGS. 2b and 2c are used inthis embodiment.

To the ends of these elastic contractable bodies are connected mountingmembers 61a and 61b shown in section in FIGS. 7a and 7b. The mountingmember 61a includes an aperture 62a formed in axial directions forreceiving one end 20a of the closure member and is integrally connectedto one end of the elastic contractable body by means of a set screw 63ascrewed into the female screw 14c of the closure member. The mountingmember 61b shown in FIG. 7b also includes an aperture 62b formed inaxial directions for receiving the other closure member 14 and isintegrally connected to the other end of the elastic contractable bodyby a snap ring 63b shown in phantom lines received in the annular groove14b of the closure member 14.

The mounting members 61a and 61b have on their outer circumferencesanchoring members 64 which expand when supplied with the pressurizedfluid thereinto. In this embodiment, apart of a tubular body 65 made ofrubber or a rubber-like elastomer is mounted on an outer circumferenceof the mounting member 61a or 61b. A clamp sleeve 66a is fitted on thetubular body 65 and caulked thereon to fix the part of the tubular body65 to the mounting member 61a or 61b. Thereafter the remaining portionof the tubular body 65 is reversed and fitted on the mounting member. Afurther clamp sleeve 66b is fitted on the reversed free portion of thetubular body 65 and calked thereon to fix the tubular body 65 to themounting member.

The pressurized fluid is supplied into the anchoring member throughsupply and exhaust passages 67a and 67b. In this embodiment, each themounting member is provided with the two supply and exhaust passages sothat a great amount of the pressurized fluid can be supplied into andexhausted from the anchoring means for a short period of time. However,the number of the openings may be increased or decreased, if required.Although the anchoring member is the tubular body made of rubber or arubber-like elastomer, a tubular body provided with wear resistantreinforcing layers may be preferably used because the tubular body abutsagainst an outer surface of the tube when supplied with the pressurizedfluid. In order to prevent the anchoring member from being damaged byrelatively sharp protrusions on the outer surface of the tube, on theanchoring member may be provided a protective cover made of a plastic,rubber or a rubber-like elastomer formed with notched grooves permittingthe anchoring member to be expanded without detrimentally affecting theexpansion of the anchoring member.

According to the invention, an elastic member 68 is arranged between themounting members 61a and 61b connected to the respective ends of theelastic contractable body 54. The elastic member is a compression coilspring in this embodiment, which is required only to have a functionelastically deformed by the mounting members 61a and 61b moving towardeach other owing to the axially contracting movement of the elasticcontractable body 54 when applying the pressurized fluid and on theother hand urging the mounting members 61a and 61b away from each otherowing to the regain of the elastic contractable body due to the decreaseof the contractive force of the elastic contractable body owing to theexhaust of the pressurized fluid therefrom. In order to ensure thearrangement of the compression spring 68 between the mounting members inthis embodiment, rims 80 are provided on ends of the mounting members.However, as the elastic contractable body limits the movement of themounting members away from each other, ends of the compression springmay only be fitted on outer circumferences of the mounting members.

The ends of the elastic contractable body provided with the anchoringmember 64 and the elastic member 68 are fixed to inner walls of theannular frames above described. For this purpose in this embodiment, theclamp sleeves 66 are embraced by substantially U-shaped mountingbrackets 69 corresponding to shapes of the clamp sleeves 66b. TheU-shaped mounting brackets 69 are fixed to the inner walls of the framesby means of set screws. In.order to securely fix the mounting bracketsand the mounting members having the clamp sleeves 66b, the mountingbrackets are formed in concaved portions with internal thread portions(not shown) spaced apart from each other, into which set screws arethreadedly screwed to prevent any relative movement therebetween.

As shown in FIG. 6a, to the outer surfaces of the frames 51 are fixedsupport brackets 70 extending therefrom at locations corresponding tothe anchoring members 64. The support brackets 70 substantially U-shapedrestraint plates 71 are secured with their openings directing radiallyinwardly of the annular shaped frames. With this arrangement, theanchoring members 64 are caused to be deformed at least inwardly of theframes when expanded, thereby securely urging and engaging the anchoringmembers 64 against the outer surface of the tube along which the devicetravels.

In this embodiment, moreover, in order to facilitate the advance andretreat of the device, rolling bodies 72 may be provided on the innerwalls of the frames as shown in FIG. 6a, although they are notessential. An inner diameter of the device including the rolling bodiesis preferably larger than an inner diameter of the device including theanchoring members 64 expanded by supplying the pressurized fluidthereinto or an outer diameter of a tube along which the device travels.The number and positions of the rolling bodies may be determinedaccording to used conditions of the device.

Respective steps of the operation of the device of this embodiment willbe explained by referring to FIGS. 8a-8e. Before starting the operation,the supply and exhaust passages 67a formed in the mounting member 61aare connected to each other through a connecting pipe 73. On the otherhand, to the other mounting member 61b is connected a supply and exhaustpipe 74 which is connected to the pressure source (not shown) andincludes valve means, for example, a three-way valve for controlling thesupply and exhaust of the pressurized fluid. One end of a furtherconnecting pipe 75, spaced from and extending in parallel with theelastic contractable body, is connected to one of the supply and exhaustpassages 67a of the mounting member 61a. The other end of the furtherconnecting pipe 75 is connected to a through-aperture (not shown) formedin the mounting member 61b. To the other end of the through-aperture isconnected a supply and exhaust pipe 76 including a control valve forcontrolling the supply and exhaust of the pressurized fluid.

FIG. 8a illustrates the traveling device arranged about at tube alongwhich the device travels. It is assumed the device advances in adirection shown by an arrow in FIG. 8a. The pressurized fluid issupplied into the anchoring member forward positioned to expand theanchoring member so that the forward positioned anchoring member ispressed to an outer surface of the tube shown in phantom line B so as tofix the frame 51 forward positioned relative to the tube.

The pressurized fluid is then supplied into each the elastic deformablebody 54 so as to expand it in diameter and contract in axial directions,so that the rearward positioned frame 51 is forwardly attracted as shownin FIG. 8b. The pressurized fluid is then supplied into the rearwardpositioned anchoring member 64 so as to expand it so that the rearwardpositioned anchoring member 64 is brought into engagement with the outersurface of the tube and the rearward positioned frame 51 is also fixedto the tube as shown in FIG. 8c.

The pressurized fluid is then exhausted from the forward positionedanchoring member to disengage it from the tube, and the pressurizedfluid is also exhausted from the elastic contractable body 54 so thatthe forward positioned frame 51 is pushed forward by the elasticrestoring force of the compression spring 68 as shown in FIG. 8d.

Thereafter, the pressurized fluid is again supplied into the forwardpositioned anchoring member, and the pressurized fluid is exhaust fromthe rearward positioned anchoring member. In this manner, thepressurized fluid is applied to the elastic contractable body and theanchoring members in the sequence above described to advance thetraveling device along the tube.

As can be seen from the above explanation, if it is required to restractthe device, the sequence of the supply and exhaust of the pressurizedfluid from the anchoring members may be changed.

In the above embodiment, the supply and exhaust of the pressurized fluidinto and out of the forward and rearward positioned anchoring membersand the elastic contractable body are carried out in a constant cycle.However, if the timing of the supply and exhaust of the pressurizedfluid into and out of the elastic contractable body is changed, theadvancing direction of the traveling device can be varied. Therefore,the traveling device according to the invention can be sufficientlyapplied to a curved tube as schematically shown in FIG. 9. Such anapplication to a curved tube is possible because the anchoring membersextend sufficient distances and contact the tube with sufficient areaswhen supplied with the pressurized fluid so that the traveling devicecan be applied to the tube even if clearances between the device and thetube are varied, and further rigidities of the elastic constractablebody and the elastic member in transverse directions are relativelysmaller than those in longitudinal directions.

Moreover, the traveling device according to the invention is not limitedto the embodiments above described. The elastic contractable body, theanchoring members and the elastic member may be separately and directlyfixed to the frames. Moreover, the elastic contractable body and theanchoring members may be integrally fixed to the frames and the elasticmember may be separately arranged between the frames. In case thatanchoring forces of the anchoring members are required to increase forloading heavy objects such as inspecting instruments, the number of theanchoring members may be increased. If increased advancing force isrequired, the numbers of the elastic contractable body and the elasticmember may be increased. The numbers and located positions of theanchoring members, the elastic contractable body and the elastic membermay be varied on the frames, if required. The traveling device can beapplicable to tubes, columns and the like having various cross-sectionsby shapes of the frames as shown in FIGS. 10a and 10b. In this manner,the invention of the present case can be modified without departing fromthe spirit and scope of the invention.

As can be seen from the above detailed explanation, the traveling deviceaccording to the invention comprises the anchoring members embracing atube outwardly by expanding the anchoring members when supplied with thepressurized fluid, and the elastic contractable bodies which drive thedevice along the tube and are of air bag type much lighter than otheractuators. Therefore, the device is light and applicable to any tubeshaving uneven surfaces and can be used in an explosive atmosphere. Inaddition, the traveling device according to the invention is applicableto tubes which are curved or flexible, because the device according tothe invention is not detrimentally affected by clearances between thetube and the device and the device is easily deformed in transversedirections. By changing shapes of the frames, the device can beapplicable to tubes of various cross-sections. Therefore, the travelingdevice according to the invention has a very wide range in which it isapplicable so that the device is very useful in industries.

FIGS. 11a and 11b are respectively a front elevation of a furtherembodiment of the traveling device traveling along an inside of a tubeand a partially cut away side view thereof. A pair of frames 101 arearranged axially spaced apart from each other and annular having aninner diameter smaller than a tube C along which the device travels. Inthe pair of frames, four elastic contractable bodies 104 are arranged inparallel with axial directions of the frames and equally spaced fromeach other in circumferential directions of the frames.

The elastic contractable bodies 54 shown in FIGS. 2b and 2c are used inthis embodiment.

Mounting members used in this embodiment are substantially similar tothose of the preceding embodiment. Therefore, the mounting members 111aand 111b and other parts will be explained by referring to FIGS. 7a and7b in which components of this embodiment are designated by referencenumerals in brackets.

To the ends of these elastic contractable bodies are connected mountingmembers 111a and 111b shown in section in FIGS. 7a and 7b. The mountingmember 111a includes an aperture 112a formed in axial directions forreceiving one end 20a of the closure member and is integrally connectedto one end of the elastic contractable body by means of a set screw 113ascrewed into the female screw 14c of the closure member. The mountingmember 111b shown in FIG. 7b also includes an aperture 112b formed inaxial directions for receiving the other closure member 14 and isintegrally connected to the other end of the elastic contractable bodyby a snap ring 113b shown in phantom lines received in the annulargroove 14b of the closure member 14.

The mounting members 111a and 111b have on their outer circumferencesanchoring members 114 which expand when supplied with the pressurizedfluid thereinto. In this embodiment, a part of a tubular body 115 madeof rubber or a rubber-like elastomer is mounted on an outercircumference of the mounting member 111a or 111b. A clamp sleeve 116ais fitted on the tubular body 115 and calked thereon to fix the part ofthe tubular body 115 to the mounting member 111a or 111b. Thereafter theremaining portion of the tubular body 115 is reversed and fitted on themounting member. A further clamp sleeve 116b is fitted on the reversedfree portion of the tubular body 115 and calked thereon to fix thetubular body 115 to the mounting member.

The pressurized fluid is supplied into the anchoring member throughsupply and exhaust passages 117a and 117b. In this embodiment, eachmounting member is provided with the two supply and exhaust passages sothat a great amount of the pressurized fluid can be supplied into andexhausted from the anchoring member 114 for a short period of time.However, the number of the openings may be increased or decreased, ifrequired. Although the anchoring member is the tubular body made ofrubber or a rubber-like elastomer, a tubular body provided withwear-resistant reinforcing layers may be preferably used because thetubular body abuts against an inner surface of the tube when suppliedwith the pressurized fluid. As an alternative, a tubular body may beused which has cord layers embedded therein in directions in practice inparallel with the axial direction. The directions of the embedded cordlayers do not detrimentally affect the expanding deformation indiameter. In order to prevent the anchoring members from being damagedby relatively sharp protrusions on the inner surface of the tube, on theanchoring means may be provided a protective cover made of a plastic,rubber or a rubber-like elastomer formed with notched grooves permittingthe anchoring member to be expanded without detrimentally affecting theexpansion of the anchoring means.

According to the invention, an elastic member 118 is arranged betweenthe mounting members 111a and 111b connected to the respective ends ofthe elastic contractable body 104. The elastic member is a compressioncoil spring in this embodiment, which is required only to functionelastically, deformed by the mounting members 111a and 111b, movingtoward each other owing to the axially contracting movement of theelastic contractable body 104 when applying the pressurized fluid and onthe other hand urging the mounting members 111a and 111b away from eachother owing to the regain of the elastic contractable body due to thedecrease of the contractive force of the elastic contractable body owingto the exhaust of the pressurized fluid therefrom. In order to ensurethe arrangement of the compression spring 118 between the mountingmembers in this embodiment, rims 130 are provided on ends of themounting members. However, as the elastic contractable body limits themovement of the mounting members away from each other, ends of thecompression spring may only be fitted on outer circumferences of themounting members.

The ends of the elastic contractable body provided with the anchoringmeans 114 and the elastic member 118 are fixed to outer walls of theannular frames above described. For this purpose in this embodiment, theclamp sleeves 116b are embraced by substantially U-shaped mountingbrackets 119 corresponding to shapes of the clamping sleeves 116b. TheU-shaped mounting brackets 119 are fixed to the outer walls of theframes by means of set screws as shown in FIG. 11b. In order to securelyfix the mounting brackets 119 an the mounting members having the clampsleeves 116b, the mounting brackets 119 are formed in concaved portionswith internal thread portions (not shown) spaced apart from each other,into which set screws are threadedly screwed to prevent any relativemovement therebetween.

As shown in FIG. 11a to the inner surfaces of the frames 101 are fixedsupport brackets 120 extending axially and outwardly of the frame atlocations corresponding to the anchoring members 114. To the supportbrackets 120 are secured substantially U-shaped restraint plates 121with their openings directing radially outwardly of the annular shapedframes. With this arrangement, the anchoring members 114 are caused tobe deformed at least outwardly of the frames when expanded, therebysecurely urging and engaging the anchoring members 114 against the outersurface of the tube along which the device travels.

In this embodiment, moreover, in order to facilitate the advance andretreat of the device, rolling bodies 122 may be provided on the outerwalls of the frames as shown in FIG. 11a, although they are notessential. An outer diameter of the device including the rolling bodiesis preferably smaller than an inner diameter of the device including theanchoring members 114 expanded by supplying the pressurized fluidthereinto or an inner diameter of a tube along which the device travels.The numbers and positions of the rolling bodies may be determinedaccording to used conditions of the device.

Respective steps of the operation of the device of this embodiment willbe explained by referring to FIGS. 12a-12e. The supply and exhaustpassages 117a in the mounting member 111a are connected to each otherthrough a connecting pipe 123. On the other hand, to the other mountingmember 111b is connected a supply and exhaust pipe 124 which isconnected to the pressure source (not shown) and includes valve means,for example, a three-way valve for controlling the supply and exhaust ofthe pressurized fluid. One end of a second connecting pipe 125 spacedfrom and extending in parallel with the elastic contractable body isconnected to one of the supply and exhaust passages 117a of the mountingmember 111a, and the other end of the second connecting pipe 125 isconnected to a through-aperture (not shown) formed in the mountingmember 111b. To the other end of the through-aperture is connected asupply and exhaust pipe 126 including a control valve for controllingthe supply and exhaust of the pressurized fluid.

FIG. 12a illustrates the traveling device arranged in a tube along whichthe device travels. It is assumed to advance the device in a directionshown by an arrow in FIG. 12a. The pressurized fluid is supplied intothe anchoring member 114 forward positioned to expand the anchoringmember so that the forward positioned anchoring member is pressed to aninner surface of the tube shown in phantom line C so as to fix the frame101 forward positioned relative to the tube.

The pressurized fluid is then supplied into each the elastic deformablebody 104 so as to expand it in diameter and contract in axial directionsso that the rearward positioned frame 101 is forwardly attracted asshown in FIG. 12b. The pressurized fluid is then supplied into therearward positioned anchoring member 114 so as to expand it so that therearward positioned anchoring member 114 is brought into engagement withthe inner surface of the tube and the rearward positioned frame 101 isalso fixed to the tube as shown in FIG. 12c.

The pressurized fluid is then exhausted from the forward positionedanchoring member to disengage it from the tube, and the pressurizedfluid is also exhausted from the elastic contractable body 104 so thatthe forward positioned frame 101 is pushed forward by the elasticrestoring force of the compression spring 118 as shown in FIG. 12d.

Thereafter, the pressurized fluid is again supplied into the forwardpositioned anchoring member, and the pressurized fluid is exhaust fromthe rearward positioned anchoring member. In this manner, thepressurized fluid is applied to the elastic contractable body and theanchoring members in the sequence above described to advance thetraveling device along the tube.

As can be seen from the above explanation, if it is required to retractthe device, the sequence of the supply and exhaust of the pressurizedfluid from the anchoring members may be changed.

In the above embodiment, the supply and exhaust of the pressurized fluidinto and out of the forward and rearward positioned anchoring membersand the elastic contractable body are carried out in a constant cycle.However, if the timing of the supply and exhaust of the pressurizedfluid into and out of the elastic contractable body is changed, theadvancing direction of the traveling device can be varied. Therefore,the traveling device according to the invention can be sufficientlyapplied to a curved tube as schematically shown in FIG. 13. Such anapplication to a curved tube is possible because the anchoring membersextend sufficient distances and contact the tube with sufficient areaswhen supplied with the pressurized fluid so that the traveling devicecan be applied to the tube even if clearances between the device and thetube are varied, and further rigidities of the elastic contractable bodyand the elastic member in transverse directions are relatively smallerthan those in longitudinal directions.

Moreover, the traveling device according to the invention is not limitedto the embodiments above described. The elastic contractable body, theanchoring members and the elastic member may be separately and directlyfixed to the frames. Moreover, the elastic contractable body and theanchoring members may be integrally fixed to the frames and the elasticmember may be separately arranged between the frames. In case thatanchoring forces of the anchoring members are required to increase forloading heavy objects such as inspecting instruments, the number of theanchoring members may be increased. If increased advancing force isrequired, the numbers of the elastic contractable body and the elasticmember may be increased. The numbers and located positions of theanchoring members, the elastic contractable body and the elastic membermay be varied on the frames, if required. The traveling device can beapplicable to tubes columns and the like having various cross-sectionsby shapes of the frames as shown in FIG. 14. Moreover, it is possible toadvance and retract the traveling device along concaved surfaces ofwalls. In this manner, the invention of the present case can be modifiedwithout departing from the spirit and scope of the invention.

As can be see from the above detailed explanation, the traveling deviceaccording to the invention comprises the anchoring members expandingwhen supplied with the pressurized fluid and engage a tube along whichthe device is to be traveled, and the elastic contractable bodies whichdrive the device along the tube and are of air bag type much lighterthan other actuators. Therefore, the device is light and applicable toany tubes having uneven surfaces and can be used in an explosiveatmosphere. Moreover, the traveling device according to the inventioncan be applied to tubes having small diameters of the order of 2^(B)(JIS G3452, nominal diameter: 2"). Moreover, the traveling deviceaccording to the invention is applicable to vertically arranged tubes towhich traveling devices of the prior art are scarcely applicable.

Contrasted with traveling devices using wheels or pawls of the priorart, the traveling device according to the invention is fixedly held ina tube by means of anchoring means expanded by supplied pressurizedfluid. Therefore, contacting areas to an inner wall of the tube arelarge and hence the compressive stresses acting upon the inner wall aresmall, so that the device can be securely held without slipping and theinner wall is not damaged. In addition, the traveling device accordingto the invention is applicable to tubes which are curved or flexible,because the device according to the invention is not detrimentallyaffected by clearances between the tube and the device and the device iseasily deformed in transverse directions. By changing shapes of theframes, the device can be applicable to tubes of various cross-sections.Therefore, the traveling device according to the invention has a verywide range in which it is applicable so that the device is very usefulin industry.

What is claimed is:
 1. A device for traveling along an elongated member,comprising; an elastic contractible body that expands; said body havinga principle axis defining an axial direction and an outward radialdirection perpendicular to a said axial direction, an expansion of saidbody in radial direction causing a contractive force in axial directionswhen the interior of the body is supplied with pressurized fluid,mounting members connected to respective ends of said elasticcontractible body, an elastic member arranged between said mountingmembers causing a force resisting to said contractive force of saidelastic contractible body, and anchoring means fixed to said mountingmembers that expand when the interior is supplied with pressurizedfluid, thereby allowing the traveling device to travel along saidelongated member by supplying the pressurized fluid into and exhaustingfrom the elastic contractible body in coordination with alternatelysupplying the pressurized fluid into and exhausting from the anchoringmeans.
 2. A traveling device as set forth in claim 1, further comprisingrolling means for helping smooth movement of the device.
 3. A travelingdevice as set forth in claim 1, wherein said elastic contractable bodycomprises a tubular body made of an elastomer, a reinforcing braidedstructure made of high strength fibers covering and reinforcing saidtubular body, and closure members closing ends of the tubular body.
 4. Atraveling device as set forth in claim 1, wherein said elastic member isa compression coil spring.
 5. A traveling device as set forth in claim1, wherein said anchoring means comprises a tubular body made of anelastomer having one end clamped to one of said mounting members, saidtubular body having the other end turned inside out and clamped to saidmounting member.